A number of techniques have been proposed for improving X-ray imaging results by improving the accuracy of the X-ray imaging system. System equipment improvements, however, address only part of the problem. It is estimated, for example, that a significant contribution to measurement inaccuracy is not due to problems with the X-ray imaging system, but is rather a result of patient motion. Because of patient movement during image acquisition, projections acquired at different time increments may not represent the attenuation line integrals of the same object. The inconsistent projections that result can lead to image artifacts, which are termed motion artifacts in the literature.
Patient motion is commonly observed during X-ray exams. For example, in conventional computed tomography (CT) exams, the normal respiration cycle can cause motion. In dental cone-beam CT (CBCT) and chest tomosynthesis, images exhibit a relatively higher number of motion artifacts, as patients are usually in sitting or standing positions and the acquisition time for projection images is longer. Repeat scans are sometimes inevitable when patient motion is excessive. X-ray imaging with low-cost CT is a challenge as a patient must sit still or stand motionless on a rotational support and be scanned by a stationary X-ray source and a stationary detector.
Problems with patient motion can be barriers to broader acceptance and use of volume imaging systems. Because of the significant patient motion, for example, the utility of low-cost CT has been limited in many developing countries.
Thus, there is a need for methods that compensate for patient motion and help to reduce the occurrence of motion-related artifacts.
The disclosure above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The invention is defined by the claims.